hedgewars/uCollisions.pas
author nemo
Thu, 01 Jul 2010 23:41:10 -0400
changeset 3608 c509bbc779e7
parent 3603 b6b1989744ef
child 3609 bc63ed514b70
permissions -rw-r--r--
Revert prior attempted optimisation. Gridding the land pays in some situations, but not all. Restricting to an upper bound might help, but overall, seems too fuzzy to be worth it. On one side is increased cost of Add/Delete + extra test on collision check, on the other is skipping the list iteration. Perhaps for large lists.

(*
 * Hedgewars, a free turn based strategy game
 * Copyright (c) 2005-2010 Andrey Korotaev <unC0Rr@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 *)

{$INCLUDE "options.inc"}

unit uCollisions;
interface
uses uGears, uFloat;

const cMaxGearArrayInd = 255;

type PGearArray = ^TGearArray;
    TGearArray = record
            ar: array[0..cMaxGearArrayInd] of PGear;
            Count: Longword
            end;

procedure initModule;
procedure freeModule;

procedure AddGearCI(Gear: PGear);
procedure DeleteCI(Gear: PGear);

function  CheckGearsCollision(Gear: PGear): PGearArray;

function  TestCollisionXwithGear(Gear: PGear; Dir: LongInt): boolean;
function  TestCollisionYwithGear(Gear: PGear; Dir: LongInt): boolean;

function  TestCollisionXKick(Gear: PGear; Dir: LongInt): boolean;
function  TestCollisionYKick(Gear: PGear; Dir: LongInt): boolean;

function  TestCollisionY(Gear: PGear; Dir: LongInt): boolean;

function  TestCollisionXwithXYShift(Gear: PGear; ShiftX: hwFloat; ShiftY: LongInt; Dir: LongInt): boolean;
function  TestCollisionYwithXYShift(Gear: PGear; ShiftX, ShiftY: LongInt; Dir: LongInt): boolean;

function  calcSlopeTangent(Gear: PGear; collisionX, collisionY: LongInt; var outDeltaX, outDeltaY: LongInt; TestWord: LongWord): Boolean;

implementation
uses uMisc, uConsts, uLand, uLandGraphics;

type TCollisionEntry = record
            X, Y, Radius: LongInt;
            cGear: PGear;
            end;

const MAXRECTSINDEX = 511;
var Count: Longword;
    cinfos: array[0..MAXRECTSINDEX] of TCollisionEntry;
    ga: TGearArray;

procedure AddGearCI(Gear: PGear);
begin
if Gear^.CollisionIndex >= 0 then exit;
TryDo(Count <= MAXRECTSINDEX, 'Collision rects array overflow', true);
with cinfos[Count] do
    begin
    X:= hwRound(Gear^.X);
    Y:= hwRound(Gear^.Y);
    Radius:= Gear^.Radius;
    ChangeRoundInLand(X, Y, Radius - 1, true);
    cGear:= Gear
    end;
Gear^.CollisionIndex:= Count;
inc(Count)
end;

procedure DeleteCI(Gear: PGear);
begin
if Gear^.CollisionIndex >= 0 then
    begin
    with cinfos[Gear^.CollisionIndex] do
        ChangeRoundInLand(X, Y, Radius - 1, false);
    cinfos[Gear^.CollisionIndex]:= cinfos[Pred(Count)];
    cinfos[Gear^.CollisionIndex].cGear^.CollisionIndex:= Gear^.CollisionIndex;
    Gear^.CollisionIndex:= -1;
    dec(Count)
    end;
end;

function CheckGearsCollision(Gear: PGear): PGearArray;
var mx, my: LongInt;
    i: Longword;
begin
CheckGearsCollision:= @ga;
ga.Count:= 0;
if Count = 0 then exit;
mx:= hwRound(Gear^.X);
my:= hwRound(Gear^.Y);

for i:= 0 to Pred(Count) do
    with cinfos[i] do
        if (Gear <> cGear) and
            (sqr(mx - x) + sqr(my - y) <= sqr(Radius + Gear^.Radius + 2)) then
                begin
                ga.ar[ga.Count]:= cinfos[i].cGear;
                inc(ga.Count)
                end
end;

function TestCollisionXwithGear(Gear: PGear; Dir: LongInt): boolean;
var x, y, i: LongInt;
    TestWord: LongWord;
begin
if Gear^.IntersectGear <> nil then
   with Gear^ do
        if (hwRound(IntersectGear^.X) + IntersectGear^.Radius < hwRound(X) - Radius) or
           (hwRound(IntersectGear^.X) - IntersectGear^.Radius > hwRound(X) + Radius) then
           begin
           IntersectGear:= nil;
           TestWord:= 0
           end else
           TestWord:= 255
   else TestWord:= 0;

x:= hwRound(Gear^.X);
if Dir < 0 then x:= x - Gear^.Radius
           else x:= x + Gear^.Radius;
if (x and LAND_WIDTH_MASK) = 0 then
   begin
   y:= hwRound(Gear^.Y) - Gear^.Radius + 1;
   i:= y + Gear^.Radius * 2 - 2;
   repeat
     if (y and LAND_HEIGHT_MASK) = 0 then
        if Land[y, x] > TestWord then exit(true);
     inc(y)
   until (y > i);
   end;
TestCollisionXwithGear:= false
end;

function TestCollisionYwithGear(Gear: PGear; Dir: LongInt): boolean;
var x, y, i: LongInt;
    TestWord: LongWord;
begin
if Gear^.IntersectGear <> nil then
   with Gear^ do
        if (hwRound(IntersectGear^.Y) + IntersectGear^.Radius < hwRound(Y) - Radius) or
           (hwRound(IntersectGear^.Y) - IntersectGear^.Radius > hwRound(Y) + Radius) then
           begin
           IntersectGear:= nil;
           TestWord:= 0
           end else
           TestWord:= 255
   else TestWord:= 0;

y:= hwRound(Gear^.Y);
if Dir < 0 then y:= y - Gear^.Radius
           else y:= y + Gear^.Radius;
if (y and LAND_HEIGHT_MASK) = 0 then
   begin
   x:= hwRound(Gear^.X) - Gear^.Radius + 1;
   i:= x + Gear^.Radius * 2 - 2;
   repeat
     if (x and LAND_WIDTH_MASK) = 0 then
        if Land[y, x] > TestWord then exit(true);
     inc(x)
   until (x > i);
   end;
TestCollisionYwithGear:= false
end;

function TestCollisionXKick(Gear: PGear; Dir: LongInt): boolean;
var x, y, mx, my, i: LongInt;
    flag: boolean;
begin
flag:= false;
x:= hwRound(Gear^.X);
if Dir < 0 then x:= x - Gear^.Radius
           else x:= x + Gear^.Radius;
if (x and LAND_WIDTH_MASK) = 0 then
   begin
   y:= hwRound(Gear^.Y) - Gear^.Radius + 1;
   i:= y + Gear^.Radius * 2 - 2;
   repeat
     if (y and LAND_HEIGHT_MASK) = 0 then
           if Land[y, x] > 255 then exit(true)
           else if Land[y, x] <> 0 then flag:= true;
     inc(y)
   until (y > i);
   end;
TestCollisionXKick:= flag;

if flag then
   begin
   if hwAbs(Gear^.dX) < cHHKick then exit;
   if (Gear^.State and gstHHJumping <> 0)
   and (hwAbs(Gear^.dX) < _0_4) then exit;

   mx:= hwRound(Gear^.X);
   my:= hwRound(Gear^.Y);

   for i:= 0 to Pred(Count) do
    with cinfos[i] do
      if (Gear <> cGear) and
         (sqr(mx - x) + sqr(my - y) <= sqr(Radius + Gear^.Radius + 2)) and
         ((mx > x) xor (Dir > 0)) then
         if ((cGear^.Kind in [gtHedgehog, gtMine]) and ((Gear^.State and gstNotKickable) = 0)) or
            // only apply X kick if the barrel is knocked over
            ((cGear^.Kind = gtExplosives) and ((cGear^.State and gsttmpflag) <> 0)) then
             begin
             with cGear^ do
                  begin
                  dX:= Gear^.dX;
                  dY:= Gear^.dY * _0_5;
                  State:= State or gstMoving;
                  Active:= true
                  end;
             DeleteCI(cGear);
             exit(false)
             end
   end
end;

function TestCollisionYKick(Gear: PGear; Dir: LongInt): boolean;
var x, y, mx, my, i: LongInt;
    flag: boolean;
begin
flag:= false;
y:= hwRound(Gear^.Y);
if Dir < 0 then y:= y - Gear^.Radius
           else y:= y + Gear^.Radius;
if (y and LAND_HEIGHT_MASK) = 0 then
   begin
   x:= hwRound(Gear^.X) - Gear^.Radius + 1;
   i:= x + Gear^.Radius * 2 - 2;
   repeat
     if (x and LAND_WIDTH_MASK) = 0 then
        if Land[y, x] > 0 then
           if Land[y, x] > 255 then exit(true)
           else if Land[y, x] <> 0 then flag:= true;
     inc(x)
   until (x > i);
   end;
TestCollisionYKick:= flag;

if flag then
   begin
   if hwAbs(Gear^.dY) < cHHKick then exit(true);
   if (Gear^.State and gstHHJumping <> 0)
   and (not Gear^.dY.isNegative)
   and (Gear^.dY < _0_4) then exit;

   mx:= hwRound(Gear^.X);
   my:= hwRound(Gear^.Y);

   for i:= 0 to Pred(Count) do
    with cinfos[i] do
      if (Gear <> cGear) and
         (sqr(mx - x) + sqr(my - y) <= sqr(Radius + Gear^.Radius + 2)) and
         ((my > y) xor (Dir > 0)) then
         if (cGear^.Kind in [gtHedgehog, gtMine, gtExplosives]) and ((Gear^.State and gstNotKickable) = 0) then
             begin
             with cGear^ do
                  begin
                  if (Kind <> gtExplosives) or ((State and gsttmpflag) <> 0) then dX:= Gear^.dX * _0_5;
                  dY:= Gear^.dY;
                  State:= State or gstMoving;
                  Active:= true
                  end;
             DeleteCI(cGear);
             exit(false)
             end
   end
end;

function TestCollisionXwithXYShift(Gear: PGear; ShiftX: hwFloat; ShiftY: LongInt; Dir: LongInt): boolean;
begin
Gear^.X:= Gear^.X + ShiftX;
Gear^.Y:= Gear^.Y + int2hwFloat(ShiftY);
TestCollisionXwithXYShift:= TestCollisionXwithGear(Gear, Dir);
Gear^.X:= Gear^.X - ShiftX;
Gear^.Y:= Gear^.Y - int2hwFloat(ShiftY)
end;

function TestCollisionY(Gear: PGear; Dir: LongInt): boolean;
var x, y, i: LongInt;
begin
y:= hwRound(Gear^.Y);
if Dir < 0 then y:= y - Gear^.Radius
           else y:= y + Gear^.Radius;
if (y and LAND_HEIGHT_MASK) = 0 then
   begin
   x:= hwRound(Gear^.X) - Gear^.Radius + 1;
   i:= x + Gear^.Radius * 2 - 2;
   repeat
     if (x and LAND_WIDTH_MASK) = 0 then
        if Land[y, x] > 255 then exit(true);
     inc(x)
   until (x > i);
   end;
TestCollisionY:= false
end;

function TestCollisionYwithXYShift(Gear: PGear; ShiftX, ShiftY: LongInt; Dir: LongInt): boolean;
begin
Gear^.X:= Gear^.X + int2hwFloat(ShiftX);
Gear^.Y:= Gear^.Y + int2hwFloat(ShiftY);
TestCollisionYwithXYShift:= TestCollisionYwithGear(Gear, Dir);
Gear^.X:= Gear^.X - int2hwFloat(ShiftX);
Gear^.Y:= Gear^.Y - int2hwFloat(ShiftY)
end;


function calcSlopeTangent(Gear: PGear; collisionX, collisionY: LongInt; var outDeltaX, outDeltaY: LongInt; TestWord: LongWord): boolean;
var ldx, ldy, rdx, rdy: LongInt;
    i, j, mx, my, li, ri, jfr, jto, tmpo : ShortInt;
    tmpx, tmpy: LongWord;
    dx, dy, s: hwFloat;
    offset: Array[0..7,0..1] of ShortInt;

begin
    dx:= Gear^.dX;
    dy:= Gear^.dY;

    // we start searching from the direction the gear came from
    if (dx.QWordValue > _0_995.QWordValue )
    or (dy.QWordValue > _0_995.QWordValue ) then
        begin // scale
        s := _1 / Distance(dx,dy);
        dx := s * dx;
        dy := s * dy;
        end;

    mx:= hwRound(Gear^.X-dx) - hwRound(Gear^.X);
    my:= hwRound(Gear^.Y-dy) - hwRound(Gear^.Y);

    li:= -1;
    ri:= -1;

    // go around collision pixel, checking for first/last collisions
    // this will determinate what angles will be tried to crawl along
    for i:= 0 to 7 do
        begin
        offset[i,0]:= mx;
        offset[i,1]:= my;

        tmpx:= collisionX + mx;
        tmpy:= collisionY + my;

        if (((tmpy) and LAND_HEIGHT_MASK) = 0) and (((tmpx) and LAND_WIDTH_MASK) = 0) then
            if (Land[tmpy,tmpx] > TestWord) then
                begin
                // remember the index belonging to the first and last collision (if in 1st half)
                if (i <> 0) then
                    begin
                    if (ri = -1) then
                        ri:= i
                    else
                        li:= i;
                    end;
                end;

        if i = 7 then break;

        // prepare offset for next check (clockwise)
        if (mx = -1) and (my <> -1) then my:= my - 1
        else if (my = -1) and (mx <> 1) then mx:= mx + 1
        else if (mx = 1) and (my <> 1) then my:= my + 1
        else mx:= mx - 1;

        end;

    ldx:= collisionX;
    ldy:= collisionY;
    rdx:= collisionX;
    rdy:= collisionY;

    // edge-crawl
    for i:= 0 to 8 do
        begin
        // using mx,my as temporary value buffer here
        
        jfr:= 8+li+1;
        jto:= 8+li-1;

        for j:= jfr downto jto do
            begin
            tmpo:= j mod 8;
            tmpx:= ldx + offset[tmpo,0];
            tmpy:= ldy + offset[tmpo,1];
            if (((tmpy) and LAND_HEIGHT_MASK) = 0) and (((tmpx) and LAND_WIDTH_MASK)  = 0)
                and (Land[tmpy,tmpx] > TestWord) then
                    begin
                    ldx:= tmpx;
                    ldy:= tmpy;
                    break;
                    end;
            end;

        jfr:= 8+ri-1;
        jto:= 8+ri+1;

        for j:= jfr to jto do
            begin
            tmpo:= j mod 8;
            tmpx:= rdx + offset[tmpo,0];
            tmpy:= rdy + offset[tmpo,1];
            if (((tmpy) and LAND_HEIGHT_MASK) = 0) and (((tmpx) and LAND_WIDTH_MASK)  = 0)
                and (Land[tmpy,tmpx] > TestWord) then
                    begin
                    rdx:= tmpx;
                    rdy:= tmpy;
                    break;
                    end;
            end;
        end;

    ldx:= rdx - ldx;
    ldy:= rdy - ldy;

    if ((ldx = 0) and (ldy = 0)) then EXIT(false);

outDeltaX:= ldx;
outDeltaY:= ldy;
exit(true);
end;

procedure initModule;
begin
    Count:= 0;
end;

procedure freeModule;
begin

end;

end.